which is a pion condensate in the \(z\)  direction
[1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}.
In \(1+1\)  dimensions, such chiral spiral condensates are ubiquitous
at low temperature and nonzero density
[5]}, [6]}, [7]}, although in general the solutions are more involved.
Given these examples, it is natural to assume that in QCD, at low temperature \(Z < 0\) 
for some range in density above \(n_{\rm sat}\) .
